Where can I get carbon steel pipes?
What are Carbon Steel Pipes?
Carbon steel pipes are basically metal alloys that are composed as a result of carbon and iron. In the process of manufacturing steel pipe, manufacturers add carbon to iron in order to solidify the overall structures and successfully strengthen the resulting metal. Carbon steel is the most cost-effective alloying material found in the market. They are also classified into four categories namely low-carbon, medium-carbon, high-carbon and ultra-high carbon steels. The steel present in the alloy is considered to be complete carbon steel only when the proportions of other evident elements present in it do not exceed any certain percentages. However, the maximum percentages that should be typically present in the alloy to form carbon steel is supposed to be 1.65 percent of manganese, 0.6 percent for copper and silicon, and 0.4 percent of copper, respectively.
Carbon steel pipe has multiple types of steel pipes, including welded steel pipe (such as ERW steel pipe, LSAW steel pipe, SSAW steel pipe) and seamless steel pipe.
Welded steel pipe is the pipe that welded by steel plate, there is a weld seam on the pipe. But seamless steel pipe is manufactured by steel bar, it has no weld seam.
They are pipes that are cast in such a manner that do not leave any seams to weaken the pipes. Furthermore, speaking of its dimensions, a pipe which has an identifying number or particular size will have the same dimensions regardless who is its manufacturer.
Types of Carbon Steel Pipes
As the development of pipe industry, pipe and pipe fittings, including pipe coupling, pipe tee, pipe elbow are more and more widely use in industrial area. There are four types of carbon steel pipe that are mostly used, and yaang as an excellent steel pipe manufacturer of China, has 24 years expenrience to produce high quality carbon steel pipe.
1. Welded steel pipe: it is also called welded pipe. It is shaped by steel plate or steel strip through bending and then welding. It is divided into seam welded pipe and spiral welded pipe. According to the application, it is divided into general welded pipe, galvanized welded pipe, oxygen blowing metric welded pipe, welded pipe, wire casing, roller tube, deep well pump pipe, auto tube, transformer, electric welding thin wall pipe, welded pipe and spiral welded pipe.
2. General welded pipe: general welding work for low pressure liquid. It uses Q195A, Q215A, Q235A steel and adopt other mild steel welding for manufacturing. Steel pipe needs to be tested through pipe pressure, bending, flattening and some experiments, and there are some specific requirements for the surface quality. Usually the delivery length is for 4 to 10m. Welded pipe wall thickness is divided into two kinds: thread steel pipe and threadless steel pipe.
3. Seamless pipe: with increasing tube welding technology and simple processing, now seamless pipe has been replaced by welded pipe. Welded pipe producing capacity has been more than 219 mm (8 inches).
4. Oxygen tube welding: it is used for steelmaking oxygen tube. It generally uses small diameter welding pipe. Its specifications range from 3/8 inch to 2 inch. The welding is made of With 8, 10, 15, 20, or Q195 steel strip. For corrosion protection, some of them need aluminized processing.
Steel Pipe Manufacturing Process
Forged Seamless Pipe Manufacturing Process
In a Forging pipe manufacturing process, a heated billet is placed in forging die that has a diameter slightly larger than the finished pipe. A hydraulic press of forging hammer with matching inside diameter is used to create cylindrical forging. Once this forging is done pipe is machined to achieve final dimension. Forging pipe manufacturing process is used to manufactured large diameter seamless pipe that cannot be manufactured using traditional methods. Forged pipes are normally used for the steam header.
In an extrusion pipe manufacturing a heated billet is placed inside the die. A hydraulic ram pushes the billet against the piercing mandrel, material flows from the cylindrical cavity between die and mandrel. This action produces the pipe from the billet. Sometimes pipe manufactured produce pipe with a high thickness which is known as mother hollow. Many secondary pipes manufactured used this mother hollow to produce pipe with different dimensions.
Welded Pipe Manufacturing Process
Welded Pipes are manufactured from Plate or continues Coil or strips. To manufacture welded pipe, first plate or coil is rolled in the circular section with the help of plate bending machine or by a roller in the case of continues process. Once the circular section is rolled from the plate, the pipe can be welded with or without filler material. Welded pipe can be manufactured in large size without any upper restriction. Welded pipe with filler material can be used in the manufacturing of long radius bends and elbow. Welded pipes are cheaper with compared to the seamless pipe and also Weak due to the weld
There are different welding methods used to weld the pipe.
- ERW- Electric Resistance Welding
- EFW- Electric Fusion Welding
- HFW- High-frequency welding
- SAW- Submerged Arc Welding (Long seam & Spiral Seam)
ERW Steel Pipe Manufacturing Process
In the ERW / EFW / HFW pipe process, first plate is formed in a cylindrical shape and the longitudinal edges of the cylinder formed are welded by flash-welding, low-frequency resistance-welding, high-frequency induction welding, or high-frequency resistance welding.
SAW Pipe Manufacturing Process
In SAW welding process, external filler metal (wire electrodes) are used to join the formed plates. SAW pipes can have a single longitudinal seam of double longitudinal seam depend on the size of the pipe. SAW pipe are also available in the spiral seam, which is continually rolled from the single plate coil. The production rate of spiral SAW pipe is very high as compared to Straight SAW pipe. However, Spiral SAW pipe are only used in low-pressure services such as water, non-critical process services etc.
Straight SAW Pipe Welding
Spiral SAW Pipe Welding
Cooling Ways of Carbon Steel Pipes
For certain special purpose steel pipe, in order to ensure the requirements of the organization of the state and physical and mechanical properties for certain special purposes, there must be a certain way of cooling and the cooling system. For example, Carbon steel pipe cooling time is the main basis to determine the length of the cooling bed. Steel pipe cooling by radiation and convection heat, proved steel temperature above 500 degrees celsius, mainly by heat radiation. 500 degrees celsius below the convection heat conduction based. It can be considered in order to reduce the the steel cooling time to reduce the cooling bed length, and to improve the operating conditions of the workshop, the forced air cooling bed. A strong urgent need in a 500 degrees celsius.Ventilation cooling time can be reduced by 40-50%.
The Cooling ways of carbon steel pipe:
The pipe cooling mode vary depending on the chemical composition of the steel pipe, size, and the desired mechanical properties, mill production, cooling going with device conditions.
1) natural air cooling. No specific requirements for ordinary steel, is normally in the atmosphere for natural cooling.
2) forced cooling. When the smaller cooling bed or mill expansion cooling bed cooling capacity, forced air-cooled, steel pipe requires a certain internal organization and mechanical properties, can be used to control the forced water cooling process.
3) slow cooling or quenching. For certain alloy steel pipe (such as bearing steel, stainless steel pipe, etc.), and sometimes slow cooling or quenching steel cooling system in order to improve steel internal organizational structure and its corresponding performance.
The Hardness of Carbon Steel Pipe
The hardness of carbon steel pipe commonly used Brinell, Rockwell, Vickers hardness of three kinds of indicators to measure.
In the steel standard, it is the most widely Brinell hardness, often expressed in the indentation hardness of the material in diameter, both intuitive and convenient. However, for a hard steel or steel thin NA.
Rockwell hardness test tube with Brinell hardness test, as are the indentation test methods. The difference is that it is a measure of the indentation depth. Steel Rockwell hardness test is a very wide application, wherein after the Brinell hardness HB HRC use in steel standard. Rockwell applicable to the determination by the extremely soft to extremely hard metal materials, which make up not Brinell method, compared with Brinell method is simple and can be read directly from the dial hardness machine hardness value. However, because of its small indentation, the Brinell hardness values better method is accurate.
The pipe is also a Vickers hardness test indentation test method for the determination of a thin metal material and a surface layer hardness. It has a Brinell, Rockwell main advantages law, and to overcome their basic shortcomings, but not as convenient method Rockwell, Vickers method is rarely used in the steel standard.
Classification of Carbon Steel Seamless Pipe
1, General seamless carbon content
Generally the carbon content of ≤ 0.25% of steel called low-carbon steel, low carbon steel annealing organization for a small amount of ferrite and pearlite, the lower its strength and hardness, ductility and toughness, ease of drawing, stamping, extrusion, forging and welding, which 20Cr steel use more widely. The steel has a certain strength, this steel after quenching and tempering has good mechanical properties, good low temperature impact toughness, temper brittleness is not obvious. Uses: In the mechanical manufacturing suitable for the manufacture of welded structures and forged, hot stamping and machining parts without high stress in the steam turbine and boiler manufacturing multi-media work for a non-corrosive pipe, flanges, header and various fasteners; also applies to the manufacture of automobiles, tractors and general machinery manufacturing SMEs carburizing, carbonitriding and other parts, such as the hand brake shoe on the car, the lever shaft, gearbox derailleur , the tractor camshaft drive gears and passive suspension balancer shafts, bushings and other internal and external balancer; in heavy, medium machinery manufacturing industry, such as forging or pressing the rod, hook and loop, lever, sleeve and fixtures.
2, Low-carbon steel seamless pipe
Low carbon steel carburizing: low carbon steel carbon content of more than 0.15% by carburizing quenching, tempering after treatment requirements for applications requiring high surface hardness, good wear resistance, shafts, bushings, sprockets, and some plastics molds and other parts. Low-carbon steel by carburizing quenching and tempering to obtain a surface treated for high carbon martensite, the center of a low-carbon martensite, thus ensuring the surface with high hardness, high wear resistance and heart Ministry has very good strength, toughness. Handbrake shoes suitable for the production, the lever shaft, gearbox derailleur, drive a tractor driven gear and camshaft, hanging balancer shaft balancer inside and outside the bushings, sleeves, clamps and other parts.
3, Carbon steel seamless pipe
Carbon steel: carbon content of 0.25% to 0.60% of carbon steel, due to an increase in steel pearlite content, its strength and hardness increase over the previous hardness after quenching can be significantly increased. High strength quenched and tempered carbon steel, has a certain plasticity and toughness, good machinability, using quenching get good mechanical properties, hardenability poor. For the manufacture of high strength requirements, toughness middle parts. Typically used in quenched and tempered or normalized state. In order to make the necessary toughness of steel and eliminate the residual stress should be after quenching and tempering of steel into patenting.
Advantages of Carbon Steel Pipe
The main ingredients of welded carbon steel pipe are iron and carbon. Due to the tensile strength attained by the composition of carbon and steel, these pipes are commonly used in industrial sectors. The usage of black steel pipe is similar to the carbon steel pipes. Both of them can be utilized to convey oils and other forms of liquids.
These pipes are preferred by the clients who are responsible for the construction of heavy industrial work. They can be used for the production of huge parts of mammoth machinery, such like large ships. The ship manufacturers have confidence in the strength of the pipes. Carbon pipes can bear vibration and harsh environment. In fact, you can find the existence of these pipes in the construction of series of national infrastructure.
The structure built from these pipes can endure the damage of serious natural disasters including earthquakes and floods. Steel is the best solution while counting on strength. While it is used to create pipes, the advantages are obvious. For instance, if the pipes need to be buried underground and endure the pressure from the soil, the steel pipes are the best alternative solution. They will not break like plastic pipes and they would not rot.
Even though the thickness of steel pipes is thinner than plastic pipes, they are much more durable. The combination of carbon and steel have improved the elasticity at the same time. These pipes with different thickness can be used to convey different forms of materials, both gases and liquids can be transferred by them. When you need to select the proper type, you need to try to choose the pipes with suitable diameters. The seamless pipes reduce the risk of leakage due to the lack of joints. And so there is no need to worry while using them to build pipelines.
Application of Carbon Steel Pipe
Carbon steel pipes are the ideal choice for transporting water, sewage, and other compatible fluids. Being highly resistant to shock or vibration, the fluctuating water pressure or shock pressure from a water hammer have no ill-effects on steel pipes. Heavy traffic conditions put much pressure on roadway foundations, making carbon steel pipes the primary choice when laying water pipelines under roadways.
Industrial Heating, Condensation, Steam
Carbon steel pipes are widely used in industrial processes involving high heat, extreme cold, or even transporting gases such as steam. Heating systems use thin-wall, straight bead, precision carbon steel pipes with a lower level of carbon content. A layer of zinc is applied to the outside of the pipe using heat treatment.
The pipes go through rigorous testing for use in closed heating systems, with or without antifreeze, and for dry and synthetic oil compressed air systems. Externally galvanized carbon steel pipes are used for circulating heating systems and internally galvanized carbon steel pipes are used for sprinkler and compressed air systems.
ASTM / ASME
|Product name||Executive standard||Dimension (mm)||Steel code/ Steel grade|
|Black and Hot-dipped Zinc-coated Steel Pipes Seamless||ASTM A53||0.3~1200 x 1.0~150||GR.A, GR.B, GR.C|
|Seamless Carbon Steel for High Temperature Service||ASTM A106||10.3~1200 x 1.0~150||GR.B, GR.C|
|Seamless Cold-drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes||ASTM A179||10.3~426 x 1.0~36||Low Carbon Steel|
|Seamless Carbon Steel Boiler Tubes for High Pressure||ASTM A192||10.3~426 x 1.0~36||Low Carbon Steel|
|Seamless Cold-drawn Intermediate Alloy Steel Heat-exchanger and Condenser Tubes||ASTM A199||10.3~426 x 1.0~36||T5, T22|
|Seamless Medium-carbon Steel Boiler and Superheater Tubes||ASTM A210||10.3~426 x 1.0~36||A1, C|
|Seamless Ferritic and Austenitic Alloy Steel Boiler, Superheater and Heat-exchanger Tubes||ASTM A213||10.3~426 x 1.0~36||T5, T9, T11, T12, T22, T91|
|Seamless Carbon and Alloy Steel for Mechanical Tubing||ASTM A333||1/4″~42″ x SCH20~XXS||Gr1, Gr3, Gr6|
|Seamless and Welded Carbon Steel Pipes and Alloy Steel Pipes for Low Temperature Use||ASTM A334||1/4″~4″ x SCH20~SCH80||Gr1, Gr6|
|Seamless Cold-drawn Carbon Steel Feedwater Heater Tubes||ASTM A556||10.3~426 x 1.0~36||A2, B2|
Steel typically is considered to be carbon steel when the proportions of other trace elements in it do not exceed certain percentages.
|Product name||Executive standard||Dimension (mm)||Steel code/ Steel grade|
|Seamless Steel Tubes for Elevated Temperature||DIN 17175||10~762 x 1.0~120||St35.8,St45.8, 10CrMo910, 15Mo3, 13CrMo44, STPL340, STB410, STB510, WB36|
|Seamless Steel Tubes||DIN 1629||13.5~762 x 1.8~120||St37.0, St44.0, St52.0|
|Seamless Precision Steel Tube||DIN 2391||4.0~60.0 x 0.5~8||St35, St45, St52|
|Seamless Steel Tubes||DIN 2440||13.5~165.1 x 1.8~4.85||St33.2|
Carbon steel pipe specification, Standard and identification
Carbon steel pipe is used to transport fluids and gases in a variety of pneumatic, hydraulic, and process applications.
ASTM/ ASME– Standards for pipes
Carbon steel tube mechanical properties
Carbon steel tube mechanical properties is generated in the carbon steel smelting defect smelting and casting process, such as segregation, non-metallic inclusions, porosity, shrinkage and cracks.
|Tensile strength, MPa(min)||Yield strength, MPa(min)||Elongation, %(min)|
Mechanical properties of API-5L carbon tube
|Steel Grade||Tensile strength, MPa(min)||Yield strength, MPa(min)||Elongation, %|
Carbon steel is a metal alloy that is formed as a result of combining iron and carbon. Steel typically is considered to be carbon steel when the proportions of other trace elements in it do not exceed certain percentages.
Carbon steel pipe rusting
Carbon steel pipe anti-rust oil: it is with a high corrosion resistance and adhesion,which does not contain harmful substances such as formaldehyde, benzene, heavy metals, environmental protection and the operator’s physical and mental health. it become into a transparent light filmcan be used as the ultimate anti-corrosion coating can also be used as anti-rust primer after drying. Closed film with excellent light, smooth, anti-discoloration resistance, corrosion resistance and high adhesion.
When carbon steel pipe rusting, and some contain a small amount of grease, it is recommended that after processing preparations, pre-treatment before the use of environmentally friendly degreasing rust one surface rust treatment products, or accessories are using coated anti-rust oil is isolated material contact with the air, but it is not the surface into the passivation film and isolated immediately after the expiration of the reservoir surface and the substrate will be a lot of rust layer, the role of microorganisms to provide a source of nutrition, use water-based dry ultrafine particles in the film’s blunt, dense material combination of anti-rust agents, anti-rust excellent performance, easy maintenance, environmental health, improve the quality of the workshop environment.
The details of steel pipe derusting methods:
Component: surfactant, corrosion and preservatives.
Features: iron, steel and other workpiece surface oil, corrosion and other one-time removal of the cleaning.
Use: apply to the processes of iron and steel castings and alloy products, such as surface cleaning processing.
Environmental Security: The solution for the water-soluble degreasing rust liquid; does not produce volatile toxic substances.
Carbon steel pipe density
Density is calculated by dividing the mass by the volume. The density of carbon steel is approximately 7.85 g/cm3 (0.284 lb/in3).
Steel is much denser than water but shaped appropriately, the density may be reduced (by adding air spaces), creating a steel ship that floats. Likewise a life jacket reduces the overall density of the person wearing it, enabling him to float much easier.
There is not one value for density that is the same for all types of steel. Different steels are different alloys, although I wouldn’t have thought the values would vary greatly since all are largely steel.
The heat treatment of carbon steel pipe
The performance of steel material mainly refers on mechanical properties, physical properties, and process performance. Heat treatment will bring different metallurgical structure and corresponding performance for the steel pipe, so could be better applied in different industrial or the oil gas services.
There are two methods to improve the properties of steel material. One method is to adjust the chemical composition, named alloying method. The other method is heat treatment. In the field of modern industrial technology, heat treatment improve steel pipe performance at dominate position.
Improving the performance of the steel is two ways, First, adjusting the chemical composition of the steel alloying; the other is the heat treatment, heat treatment and shaping deformation combination of approaches. In the field of modern industrial technology, heat treatment to improve the performance of the steel still occupy a dominant position. A wide range of steel pipe, and the appropriate standard for handling, the use of steel vary, sometimes according to their own needs but also to add additional conditions. In the standard, as one of the terms of delivery performance must meet the requirements. The performance of the steel pipes mainly refers to the mechanical properties, physical properties, the use of performance and process performance. Heat treatment by heating, insulation and cooling the steel to obtain the microstructure and corresponding to a variety of performance to meet product standards and requirements of users.
Heat treatment of carbon steel pipe can be divided into three categories, the final heat treatment processes in order to meet the performance requirements, the heat treatment that the user required to heat treatment delivery, and steel manufacturing process (heat treatment).
With other products, product standards and technical conditions required to the steel pipe commonly used in heat treatment process of hardening, tempering, normalizing and annealing. Such as: oil pipe in the casing, tubing, drill pipe, line pipe, etc., according to the level of the steel grade, it is correspondingly normalizing, normalizing plus tempering, quenching and tempering process; high-pressure boiler tubes, high pressure chemical fertilizer pipeline often used normalizing, normalizing plus tempering, quenching and tempering (thick-walled tubes) and solution treatment of austenitic stainless steel; bearing steel pipe ball annealing. Some higher alloy content steel pipe, in order to prevent the user to cracking, deformation, etc., users and standards typically require the production plant to heat treatment delivery, production plants are required, such as annealing, normalizing heat treatment. Between the heat treatment process for cold-rolled, cold drawn steel pipe production process, usually the recrystallization annealing, softening annealing. The aim is to eliminate the cold work hardening effect, reduce hardness and improve toughness in order to facilitate further cooling the deformation process to be implemented.
Seamless carbon steel pipe hardness test method
Inner diameter of seamless steel pipe is more than 6.0mm and wall thickness is less than 13mm annealed seamless steel pipe material, which can be used W-B75 Webster Hardness test with very fast, easy, suitable for rapid non-destructive of the seamless steel pipe material qualified inspection. Inner diameter of seamless steel pipe is greater than 30mm and wall thickness greater than 1.2mm seamless steel tubes, using a Rockwell hardness test HRB, HRC hardness.
Inner diameter of seamless steel pipe is greater than 30mm, wall thickness less than 1.2mm of seamless steel tubes, Rockwell superficial hardness test hardness of HRT or HRN. Diameter less than 0mm, more than 4.8mm of seamless steel pipe, pipe dedicated Rockwell hardness test HR15T hardness. When the seamless steel pipe inner diameter greater than 26mm, you can also use the Rockwell or the Rockwell superficial hardness test hardness of the pipe wall.
The tensile test uses carbon steel pipes made of samples, sample in the tensile test machine will pull to fracture, then the determination of one or several mechanical properties, usually only the determination of tensile strength, yield strength, percentage elongation and section shrinkage. The tensile test the mechanical properties of metal materials, the basic test methods, almost all metallic materials, as long as the mechanical properties required to provide a tensile test. Especially those who shape is not easy material hardness test, tensile test to become only the mechanical properties testing means. The hardness test is a hard indenter prescribed conditions slowly pressed into the surface of the sample, and then test the indentation depth or size, in order to determine the size of the material hardness. The hardness test is the mechanical performance test with the easiest, fastest and most easy to implement. Hardness test is non-destructive, the approximate conversion relationship between hardness and tensile strength values. The material’s hardness value can be converted into the tensile strength values, it has great practical significance.
Tensile test is not easy to test the strength is very convenient, so people are increasingly test hardness and less test its strength, and hardness conversion. Hardness manufacturing technology continues to progress and innovation, the original can not directly test the hardness of materials, such as seamless steel pipe, stainless steel plate and stainless steel bands, now may directly test the hardness of the Therefore, there is a hardness test is gradually replaced by the trend of the tensile test. The hardness test of the stainless steel to take into account its mechanical properties, performance and quality of this is related to the deformation of stainless steel as raw materials, stamping, cutting and other processing. Therefore, all seamless steel tubes for mechanical properties testing. Mechanical properties of the test method is mainly divided into two categories, a tensile test, hardness test.
Most of which are national standards in stainless steel also provides the tensile test and hardness test. For those not easy for hardness testing of materials, such as seamless steel pipe only requires that the tensile test. Stainless steel standard, general provisions of the cloth, Luo, Victoria three hardness test method, determination of the HB, HRB (HRC) and the HV hardness value, the provisions of the three hardness values only for one can be. Especially the newly developed portable superficial Rockwell hardness tester, pipe Rockwell hardness tester can be as thin as 0.05mm stainless steel plate, stainless steel with a thin to 4.8mm seamless steel tubes for fast, accurate hardness testing, making difficult to resolve domestic problems solved.
Low carbon steel
Low carbon steel is a type of metal that has an alloying element made up of a relatively low amount of carbon.
Low Carbon Steel. Low carbon steel is a type of steel that has small carbon content, typically in the range of 0.05% to 0.3%. Its reduced carbon content makes it more malleable and ductile than other steel types.
Hot rolled is relative to the terms of the cold-rolled, cold-rolled is in the recrystallization temperature below the rolling, and the hot rolling is carried out at above the recrystallization temperature rolling.
Hot rolled can damage the cast microstructure of the steel ingot, refinement of the crystal grains of the steel, and eliminate the defects of the microstructure, so that the the steel organization compacting, improve the mechanical properties.
This improvement is reflected in the rolling direction, so that the steel is no longer to a certain extent isotropic; pouring the formation of bubbles, cracks, and osteoporosis, under high temperature and pressure can also be welded together.
- After the hot rolling, the nonmetallic inclusions in the interior of a steel (mainly sulfides and oxides, as well as the silicate) was pressed into a sheet, stratified (laminated) phenomenon appears. The layering of the steel in the thickness direction by the pull performance deteriorated significantly, and may appear in the weld shrinkage interlayer tear. Weld shrinkage induced local strain often reach several times the yield point strain, the strain is much greater than the load caused;
- Residual stress caused by uneven cooling. The residual stress is the stress of internal self-phase equilibrium in the absence of external force, the hot-rolled steel of various cross-sectional has a residual stress such Usually steel sectional dimension is the greater, the greater the residual stresses. Residual stress is self-phase equilibrium, but the steel members in the performance external force or have a certain influence. Such as deformation, stability, anti-fatigue may adversely.
- Hot-rolled steel products, poor control of thickness and edge width. We are familiar with the thermal expansion and contraction, even if the beginning of the hot-rolled out are standard length, thickness, or there will be some negative final after cooling, this negative differential edge width wider the increasing thickness of the performance of the more obvious. So for large steel for steel edge width, thickness, length, angle, and sideline no law requires too precise. Hot-rolled steel general steel, low and medium pressure boiler pipe, high pressure boiler pipes, steel pipes, stainless steel pipe, oil cracking pipe, geological steel pipes and other steel pipe.
Other types of carbon steel include medium, high, and ultrahigh carbon steels. Medium carbon steel customarily has a carbon content ranging between 0.30 and 0.60% and a manganese content falling between 0.60 and 1.65%. It is frequently used for making products like axles, gears, shafts, and rail systems. Often used for making ultra-strength wires or spring materials, high carbon steel usually has a carbon content ranging between 0.60 and 1.0% and a manganese content ranging between 0.30 to 0.90%. Ultrahigh carbon steel, which can be used for manufacturing items like knives, is thermomechanically processed and ordinarily has a carbon content of 1.25 to 2.0%.
Brinell hardness of carbon steel pipe
Brinell hardness (HB) with a certain diameter of the steel balls or tungsten carbide balls, pressed into the pattern surface of a predetermined test force (F), after the predetermined hold time after drop test force, the diameter of the measurement sample surface indentation (L).
Brinell hardness test force divided by the the indentation spherical surface area quotient. To HBS (Ball Ball Ball Ball) the unit N/mm2 (MPa). The formula is: where: F – pressed into the metal surface of the sample test force, N; D – test steel ball diameter, mm; d – indentation average diameter mm.
Brinell hardness was measured more accurate and reliable, but generally HBS only applies 450N/mm2 (MPa) or less of a metal material, for the harder steel, or thin sheet NA.
Steel standards, brinell hardness is the most widely used, and often said that the hardness of the material, the indentation diameter d both intuitive and convenient.
Brinell hardness is the most widely used methods in carbon steel pipe hardness testing . This method uses the earliest, due to its imprint, and thus the hardness values affected by the sample organization microsegregation ingredients uneven minimal impact, test results points sprinkle a small degree, good reproducibility, can objectively reflect the objective hardness of the material.
Principle: In a predetermined detection force, a certain diameter of the steel ball is pressed into the specimen surface to maintain a certain time, and then removing the detected force, the pressure imprint diameter measurement on the specimen surface, can be calculated based on the diameter of the pressure imprint pressure marks the gravure area.
Brinell hardness test force divided by the the indentation spherical surface area quotient. Unit 9.807N/mm. The indentation Big steel ball pressed into the deep, low hardness values; vice versa hardness values to engage.
Difference between carbon steel and alloy steel
Steel is an alloy that mostly contains iron. But its properties can be changed to suit specific requirements by adding certain other elements. This explains the differences between alloy steel and carbon steel. As the name indicates, alloy steel has other elements added to it whereas carbon steel is a kind of steel having higher carbon content. There are other differences also that will be talked about in this article.
Carbon steel is also known as the iron-carbon alloy containing less than 2% carbon WC.
Generally also contain small amounts of silicon, manganese, sulfur, phosphorus and carbon steel, in addition to carbon use can be divided into carbon steel and carbon structural steel, carbon tool steel, and ease of cutting structural steel three categories. Carbon structural steel is divided into building structural steel and machinery manufacturing structural steel two kinds.
According to the carbon steel, carbon content can be divided into low-carbon steel (WC ≤ 0.25%), medium carbon steel (WC0.25% – 0.6%) phosphorus, sulfur content and high-carbon steel (WC> 6%) can be divided into ordinary carbon steel (containing phosphorus, sulfur higher), high-quality carbon steel (containing phosphorus, low sulfur) and high quality steel (phosphorus, sulfur less), generally, the higher carbon content, the higher the hardness, higher strength but lower ductility.
Alloy steel is a type of steel that has presence of certain other elements apart from iron and carbon. Commonly added elements in alloy steel are manganese, silicon, boron, chromium, vanadium and nickel. The quantity of these metals in alloy steel is primarily dependent upon the use of such steel. Normally alloy steel is made to get desired physical characteristics in the steel.
Alloy steels are divided into low alloy steels and high alloy steels. When the percentage of added elements goes past 8 (in terms of weight), the steel is referred to as high alloy steel. In cases where added elements remain below 8% by weight of the steel, it is a low alloy steel. Low alloy steels are more common in the industry. In general, addition of one or more of such elements to steel makes it harder and more durable. Such steel is also resistant to corrosion and tougher than normal steel. To alter the properties of steel, it needs heat treatment when elements are added to it.
To keep the alloy steel weldable, carbon content needs to be reduced. As such carbon content is lowered down to 0.1% to 0.3% and alloying elements are also decreased in proportion. These alloys of steel are known as high strength, low alloy steels. You would be surprised to know that stainless steel is also an alloy steel with a minimum of 10% of chromium by weight.
In brief Alloy Steel vs Carbon Steel:
- There are many types of steels such as alloy steel and carbon steel
- As the names signify, alloy steel is the type of steel formed by addition of various other elements in the steel through heat treatment.
- Carbon steel on the other hand is steel that has primarily carbon in it and does not require any minimum percentage of other elements.
- Carbon steel is the type of steel predominantly used in the US
- Stainless steel is a kind of alloy steel
Analysis on the weld defects on the low carbon steel pipeline
At the time of the extinction, the protective effect of the arc and sla is weakening and easy to be prone porosity and other defects in the crater.
The extent of the defects can be removed when the next track weld joints, eliminating the effects of good or bad depends on the joint when melting, melting the extent possible, the more completely eliminate such defects. Power station boiler heating surfaces are mostly calandria disorder, the disorder in the form of a joint decision more on the road when the joints of the crater of the weld short duration of action, it is difficult to overcome the defects, could easily lead to discharge pipe welded joints appear Groups holes.
When manual electric arc welding affect the tilt angle of the protective effect of weld large, if not in the welding process always maintain the correct angle, will inevitably cause harmful gases outside intrusion, with no increase in the correct angle welding seam length, will forming a strip vent. When the level of the large diameter pipe is fixed for all position welding head for welding, due to the height so that the welder must take the welding positions are different at different positions in order to maintain operation of the angle bar. In the oblique oblique flat welding and overhead welding positions, welder in posture more difficult, it is difficult to maintain the correct angle bars shipped, so the weld these locations prone to strip holes. Small diameter pipe welding defect occurs mainly due to the shelf erection is not ideal. Speed and swings transport determines the thickness of the single bead, shipped fast speeds make the electrodes need to quickly change the angle, or can not form an effective slag = gas joint protection. After bottoming thin-walled tube welding requirements cover thin, hand welding should keep fast transport speeds, there would strip holes.
Fin tube welded joints tend to think in a row counterpart, plus welding shrinkage deformation, resulting in more difficult to maintain proper clearance counterparts, when welding backing of melting degree bevel weakened, resulting in lack of penetration. Stainless steel welding consumables molten metal flow is poor, and the heat quickly, the heat is not easy to concentrate, which resulted in the arc heating and melting of the base metal or weld metal is more difficult to fill, the formation of incomplete penetration defects. Often large diameter thick wall pipe, joints when welding backing if not root penetration, is caused by lack of penetration; large diameter thick-walled tube blunt edge is large, are likely to cause incomplete penetration.
When soldering, the thickness of the filler metal will affect the slag floating overflow, slag defects can not be completely overrun if the slag is formed. Large diameter thick-walled pipe welding is often used when a large current, the larger the thickness of the single-pass welding slag completely floating more difficult to form a slag defects. Liquidity filler metal slag has great influence on the generation of defects. Stainless steel material of the molten metal poor mobility, coupled with the use of a small current narrow weld operation, the weld metal solidification, difficult to fully surfaced weld slag, slag formation of defects. Horizontal welding, soldering oblique welding head adopts lane, lane number as handled badly, can cause weld “dead”, have a greater chance of slag defects.
TIG hit bottom as thin, stress will make it happen when filling tear caused by the formation of cracks; not timely sub-layer backing weld after welding, but also the cause of cracks. Preheat temperature and improper welding rod storage, improper use, will increase the chance of cracks.
Carbon steel pipe standard length
Delivery standard length of carbon steel pipe, also known as user requirements length or the length of the contract, there are four provisions in the existing standards:
A, Normal length(also known as non-random length): any length within the length of the standard required and no fixed length requirements are usually called normal length.
B, Cut length: cut length should be within the range of usual length, which is required in the contract a fixed length dimension. But the actual operation is definitely cut out and it is unlikely, so the standard specifies the length of the length positive deviation allowed. Production decreased length than the length of the tube length of pipe is usually the yield big margin, producers proposed fare increase is reasonable. Markups enterprises are not consistent, usually based on the base price increase of about 10%.
C, Double length: according to the requirement of order, the length is the integer multiple and referred to as double length. double length should be within the range of usual length, the contract should specify a single double length and composition of the total length multiples. In practice, the total length should be based on the allowed positive deviation with 20mm, together with the double length of each single incision margin should remain. If the standard deviation is no double length and cutting margin requirements , should be negotiated by both parties and specified in the contract. Times longer scale length the same length as the production will bring a significant reduction in the yield, so the producers proposed increase is reasonable, and its rate of increase with the length of the rate of increase substantially the same length.
D, Scope length: the length of the range is within typically normal length range, when the user requests a fixed range in which the length of time, they need to be specified in the contract.
Carbon steel defect
Carbon steel is formed when two elements, iron and carbon, is combined with carbon being used as the alloying element.
Carbon steel defect is caused by the equipment, processes and operations in carbon steel smelting and rolling (forging) process, including scarring, cracks, residual shrinkage, layered, white point, segregation, non-metallic inclusions, such as osteoporosis and banded.
No scarring and the base steel surface weld metal or metalloid scar blocks. Some parts of the body is connected with the base, was tongue; others not connected with the matrix, scaly. The latter is sometimes off during processing, forming pits. Steel (cast) scarring caused by scar generally have lower non-metallic inclusions visible to the naked eye. Scarring defects directly affect the quality and appearance of the mechanical properties of the steel. Scarring are not allowed in the presence of finished steel. Scarring can be grinding parts for repair after repair of steel grinding size should meet the standard requirements.
Cracks formed by the shape and name a variety of reasons, such as crack, transverse crack, crack, crack, hairline, burst (loud crack), rattle (Jiao crack), rolling and shear crack bifida. From steel making, rolling into steel processing almost every procedure has factors causing cracks.
The molten steel during solidification, due to the volume shrinkage in the ingot or billet has not been sufficiently filled central portion formed by a tubular or dispersion holes. Before thermal processing, because cutting head is too small or craters deeper, causing endless resection, the residual part is called residual shrinkage. The residue was distributed in the shrinkage at the upper center of the ingot, and the ingot through the top is called a cratering.
Binding and do not appear on the two-layer structure of the steel substrate. Stratification generally parallel to the surface pressure processing, in longitudinal section transverse black lines are low magnification specimen. Layered severe cracks occurred in fractures tend to have iron, non-metallic inclusions and severe segregation substances. Killed steel ingot ingot boiling craters and holes by the end of the balloon and rolling (forging) can not be welded together to produce stratification. Large inclusions in steel and can produce severe segregation layering. Layering is not allowed in the steel defects seriously affect the use of steel.
On steel vertical, cross-sectional acid leaching test piece, there’s no rule of different lengths hairline. It is the low times in the transverse specimen radial, concentric or irregularly distributed, multi-center, or from the steel surface has a certain distance. Steel fracture in the transverse or longitudinal, circular or oval white highlights. Average diameter of 3 ~ 10mm. Steel plate in the longitudinal, transverse fracture characteristic white spots is not obvious, but the fracture presented to strip or oval-shaped white spots in z. When using fracture checks white spots, it is best to first quenched specimens and quenched.
Uneven steel components. This phenomenon is not only common element (such as carbon, manganese, silicon, sulfur, phosphorus) uneven distribution, but also non-metallic inclusions and gas distribution uniformity. The reason is that the segregation arising during solidification of molten steel, the resulting crystals separators. Often associated with the degree of segregation ingot, steel, smelting and casting operation conditions. Alloying elements, segregation of impurities and gases, with the casting temperature and the casting speed, the more serious the degree of segregation. Even steel using electromagnetic stirring can reduce the degree of segregation. In addition, the increase in steel cleanliness is an important measure to reduce segregation.
The steel contains a metal component and the substrate different nonmetallic materials. It destroys the continuity and isotropic properties of the metal matrix. According to the source of non-metallic inclusions can be divided into endogenous inclusions, foreign inclusions and their mixtures. Endogenous inclusions are deoxidation and various physical and chemical reaction performed by the formation of crystals, mainly steel oxygen, sulfur, nitrogen, among other components with the reaction product.
Not dense thermal etching phenomenon steel sectional tissue specimen. Thermal etching on the steel cross-section specimen, there are many pores and black specks promoter, rendering the phenomenon is not dense tissue, called loose when one of these pores and black specks distributed throughout the sub-test piece, concentrated in the center of the center is called osteoporosis . Thermal etching in the longitudinal specimens showed loose stripes of different lengths, but careful observation or observation with 8 to 10 times magnifying glass, striped no depth. Porosity was observed by scanning electron microscopy or streaks can be found distal dendrites are free of surface features metal crystals.
After thermal processing of low-carbon steel, the microstructure of ferrite and pearlite parallel along the rolling direction, zonal distribution, formed steel banded structure. Banded structure is essentially a steel tissue uneven performance, the impact properties of the steel, producing equipment to the opposite sex. Banded lower steel ductility, toughness and reduction, especially greater impact on the transverse mechanical properties.
Condition on delivery:
|BK||No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.|
|BKW||After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits.|
|Annealed||GBK||After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum.|
|Normalized||NBK||The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum.|
Difference between mild steel and carbon steel pipe
Difference between mild steel and carbon steel pipe refers to the machining surface has a smaller spacing and small valley roughness.
Two peaks or troughs which the distance between the two (the pitch) is small (at 1mm or less), it is difficult to distinguish with the naked eye, so it belongs to the micro geometry errors. Smaller the surface roughness, the surface is more smooth. The size of the surface roughness on the performance of mechanical parts have a great impact.
Mild steel is the type of carbon steel where it contains very low amounts of carbon. Approximately, it is 0.16–0.29% by weight. This steel is very cheap and most commonly used. It is malleable and ductile but has low tensile strength. Mild carbon cannot be hardened by heat treatment.
Carbon steel is used to denote steel with carbon as the main alloying element. In carbon steel, the properties are mainly defined by the amount of carbon it has. For this alloy, the amounts of other alloying elements like chromium, manganese, cobalt, tungsten are not defined. There are four types of carbon steel. This categorization is based on the carbon content. Mild and low carbon steels contain very low carbon percentages. There are three other types of carbon steel as medium carbon steel, high carbon steel and ultra high carbon steel. In the higher carbon steels, the carbon level varies between 0.30–1.70 % by weight. Medium carbon steel has 0.30–0.59% carbon content whereas the high steel has 0.6-0.99%. Ultra high carbon steel has 1.0-2.0% of carbon content. They can undergo heat treatment successfully. Therefore, normally these are very strong and hard, but ductility can be low.
Mild steel has very low carbon percentage compared to other carbon steel. Mild steel has high ductility, and it is malleable, whereas other carbon steel types have low ductility. Mild carbon cannot be hardened by heat treatment, but other types of carbon steel can be hardened by heat treatment. Mild steel is less strong and harder than other carbon steel types. Steel surface roughness Ra is usually expressed.
Pipe surface roughness is mainly manifested in the following aspects:
- Surface roughness of the wear parts. The rougher the surface, with the effective contact surface area between the smaller, the greater the pressure, the faster the wear.
- the nature of the surface roughness with stability. For clearance fit, the rougher the surface, the more easy to wear, so that the work process gap increases; against interference fit, because the assembly will squeeze micro convex peak level, reducing the actual effective interference, reduce the connection strength.
- Surface roughness fatigue strength of parts. The rough parts of the surface of the trough there is a big, they look like sharp as gaps and cracks, the stress concentration is very sensitive, thus affecting the fatigue strength of parts.
- Surface roughness of parts corrosion resistance. Rough surface, easy to corrosive gas or liquid through the valley penetrate microscopic surface to the metal inner layer, resulting in surface corrosion.
- Surface roughness of the sealing parts. Rough surfaces can tightly fit between the gas or liquid through the gap between the contact surface leakage.
- surface roughness of parts contact stiffness. Parts with surface contact stiffness is under external force, the ability to resist deformation of the contact. The stiffness of the machine depends largely on the contact stiffness between the various parts.
- affecting the measurement accuracy of parts. Parts measured surface and measuring tools to measure surface roughness will directly affect the measurement accuracy, especially in precision measurement. In addition, the surface roughness of the part plated coating, thermal resistance and contact resistance, and radiation reflectance properties, resistance to the flow of liquids and gases, the flow of current conductor surface and so have different degrees.
Why Do We Choose to Use Carbon Steel Pipe?
There are more and more people choose to use carbon steel pipe in the construction.
Why? Next, Yaang will show you some advantages of carbon steel pipe for all of you.
A.Safe and durable
We all know that steel is a frequently-used material because it is durable and safe. Since steel is non-combustible and makes it harder for fire to spread, it is good to use when building homes. Carbon steel pipe is highly resistant to shock and vibration. Fluctuating water pressure or shock pressure from a water hammer have little effect on steel. And carbon steel pipe is practically unbreakable in transport and service, and for this reason it is okay to lay water mains under roadways.
B. Environmental protection
Using steel for pipes is not only safer for people, but it is safer for the earth. Steel can be recycled. Each year, about 70 percent of all steel is recycled in North America, more than paper, aluminum, plastic and glass combined. Steel products can be recycled over and over without losing any strength. Almost half the world’s steel is produced in electric plants that use recycled scraps and generate no CO2 emissions.
For any given pressure, carbon steel pipes can be made much thinner than pipes made from other materials, so they have a greater carrying capacity than pipes of other materials with the same diameter. The unmatched strength of steel piping increases longevity and reduces the need for replacement and repairs.Its versatility also makes it cost-effective. Yaang can make pipes in many dimensions, from less than an inch to over five feet. They can be bent and wrought to curve and fit anywhere they need to be. Joints, valves and other fittings are widely available at good prices.
Do I need carbon steel?
It depends on your application. You may need steel, but you may need plastic, or even concrete or ceramic pipes may work for your needs. Carbon steel pipes do have a wide range of uses. For example, they are used for low pressure conveyance of gas, water, oil, air steam or other fluids. They are used in machinery, buildings, sprinkler systems, irrigation systems, and water wells.
Is it hard to work with carbon steel?
As with any materials, carbon steel pipes do offer their own challenges when working with them. The joining method is generally dictated by wall thickness, which in turn is dictated by size and use. There are a variety of carbon steel pipe fittings that can be used. In addition to joining, cutting carbon steel pipes offers its own challenges. Again though, the method for cutting is determined by the thickness and hardness of the pipe. Cutting carbon steel pipes could be accomplished by several methods ranging from handheld band saw to cutting torch.
Where can I get carbon steel pipes?
Yaang Pipe Industry (www.steeljrv.com) has every type of carbon steel pipes you need. Even if you haven’t found it elsewhere, we can get it or we can make it.
Source: China Carbon Steel Pipes Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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